1. Field of the Invention
The present invention relates to a mobile communication service for performing electronic mail communication through a high speed mobile communication network.
2. Description of the Related Art
Network infrastructures, portable telephones and data-card terminals, which are adapted for high speed communication networks, have become widespread. Occasions for using electronic mail to send large volume files and data have been increasing.
In such communication environments, in order to efficiently transmit/receive electronic mail containing a large volume of data utilizing a high speed communication network, for example, a user of a mobile terminal which utilizes a wireless communication network is required to transmit/receive electronic mail after confirming that a connection to a high speed communication network has been established.
Since the introduction of wireless high speed communication networks is progressing in stages, multiple wireless communication networks of different communication speeds coexist. Therefore, a user of a mobile terminal is normally unable to recognize the communication speed of the communication network to which the mobile terminal is connected.
Moreover, when a user of a mobile terminal receives electronic mail, if the mobile terminal is inside the coverage area of the wireless communication network, the user of the mobile terminal manipulates electronic mailer of the mobile terminal in order to receive the electronic mail so that the electronic mail is received by the mobile terminal from an incoming mail server at an electronic mail center.
On the other hand, when the mobile terminal is outside the coverage area of the network, the user is required to perform the procedure for receiving electronic mail after the mobile terminal enters the coverage area of the wireless communication network.
Further, when transmitting electronic mail as well, if the mobile terminal is inside the coverage area of a wireless communication network, a user of the mobile terminal performs the procedure for transmitting electronic mail so that the electronic mail is transmitted.
On the other hand, when electronic mail is to be transmitted while the mobile terminal is outside the coverage area of the network, upon receiving a transmission instruction of electronic mail from a user of a mobile terminal, the electronic mailer enters a transmission waiting state (a transmission standby state). In this case, upon detecting that the mobile terminal is inside the coverage area of the communication network, the electronic mailer is automatically activated so that the electronic mail is transmitted.
However, in this case, the user of the mobile terminal is unaware of the communication speed of the wireless communication network to which the mobile terminal has connected. Because of this, there is a risk, for example, that transmission/reception of electronic mail containing a large volume of files or data is initiated on a low speed communication network (line) or a user inadvertently performs the procedure for transmitting/receiving electronic mail containing a large volume of files or data by using a low speed communication network (line).
In such a case, a loss of data, or the erroneous transmission of data, which is to be transmitted, is more likely to occur. Further, a problem will arise in that there may be an additional increase in communication time and communication cost. Furthermore a problem may arise in that the communication speed is further reduced due to the increase in communication traffic.
To cope with the above described problems, there is disclosed a method of notifying the user of a mobile terminal of the communication speed of the wireless communication network to which the mobile terminal is currently connected (see Japanese Patent Laid-Open No. 2003-209870 and No. 2006-173778).
However, in the technology according to Japanese Patent Laid-Open No. 2003-209870 and 2006-173778, a problem exists in that even if a user is notified of a connection with a high speed communication network, the user cannot transmit/receive electronic mail if the user does not notice the notification or if the user cannot operate the mobile terminal, thus reducing efficiency.